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LOANS AND ALLOWANCE FOR LOAN LOSSES - Summary of Impaired Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 | Dec. 31, 2018
Unpaid Principal Balance [Abstract] |  |
Unpaid Principal Balance, With no related allowance recorded | $ 5,959 | $ 8,356
Unpaid Principal Balance, With related allowance recorded | 3,049 | 3,000
Unpaid Principal Balance | 9,008 | 11,356
Recorded Investment [Abstract] |  |
Recorded Investment, With no related allowance recorded | 5,959 | 8,356
Recorded Investment, With related allowance recorded | 3,049 | 3,000
Recorded Investment, With related allowance recorded | 9,008 | 11,356
Related Allowance [Abstract] |  |
Related Allowance | 877 | 493
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded | 1,869 | 8,202
Average Recorded Investment, With related allowance recorded | 895 | 1,348
Average Recorded Investment, With related allowance recorded | 2,764 | 9,550
Commercial and industrial |  |
Unpaid Principal Balance [Abstract] |  |
Unpaid Principal Balance, With no related allowance recorded | 326 | 837
Unpaid Principal Balance, With related allowance recorded | 157 | 185
Recorded Investment [Abstract] |  |
Recorded Investment, With no related allowance recorded | 326 | 837
Recorded Investment, With related allowance recorded | 157 | 185
Related Allowance [Abstract] |  |
Related Allowance | 57 | 64
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded | 83 | 842
Average Recorded Investment, With related allowance recorded | 41 | 300
Construction and development |  |
Unpaid Principal Balance [Abstract] |  |
Unpaid Principal Balance, With no related allowance recorded | 1,250 | 720
Unpaid Principal Balance, With related allowance recorded |  | 530
Recorded Investment [Abstract] |  |
Recorded Investment, With no related allowance recorded | 1,250 | 720
Recorded Investment, With related allowance recorded |  | 530
Related Allowance [Abstract] |  |
Related Allowance |  | 4
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded | 312 | 518
Average Recorded Investment, With related allowance recorded |  | 44
Commercial real estate |  |
Unpaid Principal Balance [Abstract] |  |
Unpaid Principal Balance, With no related allowance recorded | 2,700 | 5,168
Unpaid Principal Balance, With related allowance recorded | 2,753 | 1,985
Recorded Investment [Abstract] |  |
Recorded Investment, With no related allowance recorded | 2,700 | 5,168
Recorded Investment, With related allowance recorded | 2,753 | 1,985
Related Allowance [Abstract] |  |
Related Allowance | 746 | 341
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded | 1,107 | 5,138
Average Recorded Investment, With related allowance recorded | 764 | 677
Farmland |  |
Unpaid Principal Balance [Abstract] |  |
Unpaid Principal Balance, With related allowance recorded | 139 | 140
Recorded Investment [Abstract] |  |
Recorded Investment, With related allowance recorded | 139 | 140
Related Allowance [Abstract] |  |
Related Allowance | 74 | 78
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded |  | 62
Average Recorded Investment, With related allowance recorded | 35 | 147
1-4 family residential |  |
Unpaid Principal Balance [Abstract] |  |
Unpaid Principal Balance, With no related allowance recorded | 1,450 | 1,223
Unpaid Principal Balance, With related allowance recorded |  | 160
Recorded Investment [Abstract] |  |
Recorded Investment, With no related allowance recorded | 1,450 | 1,223
Recorded Investment, With related allowance recorded |  | 160
Related Allowance [Abstract] |  |
Related Allowance |  | 6
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded | 294 | 1,132
Average Recorded Investment, With related allowance recorded | 55 | 128
Multi-family residential |  |
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded |  | 54
Agricultural |  |
Unpaid Principal Balance [Abstract] |  |
Unpaid Principal Balance, With no related allowance recorded | 233 | 408
Recorded Investment [Abstract] |  |
Recorded Investment, With no related allowance recorded | 233 | 408
Average Recorded Investment [Abstract] |  |
Average Recorded Investment, With no related allowance recorded | $ 73 | 456
Average Recorded Investment, With related allowance recorded |  | $ 52

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